Device for cutting bore hole pipes



March 1952 M. RINGLER 3,024,842

DEVICE FOR CUTTING BORE HOLE PIPES Filed Sept. 4, 1958 Fig.1 Fig.2 F495INVENTOR. /7/; UR rc r Ewe/.5?

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3,024,842 Patented Mar. 13, 1962 3,024,842 DEVICE FOR CUTTING BORE HOLEPIPES Maurycy Ringler, 3 Beth Oren St., Yad Eliahu, Tel Aviv, IsraelFiled Sept. 4, 1958, Ser. No. 758,942 Claims priority, applicationIsrael Feb. 4, 1958 4 Claims. (Cl. 166-55.6)

In sinking a Well the drill is positioned at the end of a shaftconstituted by steel tubing. As the drilling proceeds pipes aresuccessively lowered into the bore hole lining the latter. Thus the saidhollow shaft extends within a pipe casing reaching down into the borehole.

It sometimes happens that for one reason or another the hollow shaft(the drill pipes) or the drill collar has to be cut off so as toretrieve it from the bore hole. For this purpose cutters are used ofmore or less complicated design. Such cutters have to be lowered throughthe narrow annular space between the said shaft and the casing and aretherefore as thin walled as possible. That necessity imposes limitationson the designer and that is the reason why such cutters are not entirelysatisfactory. Their main disadvantage is that they can cut through thinwalled drill pipes up to, say, 12 mm. only so that they cannot sever aso called drill collar with a Wall thickness of, say, 45 mm. For suchreason it may even happen that a bore hole has to be abandoned.

It is the object of the present invention to provide a cutter of novelconstruction, and more specifically one which can be used for cuttingdrill collars.

It is another object of the invention to provide a cutter of simpleconstruction which can easily be lowered in the bore hole to itseventual position of work.

These and other objects of the invention will become clear from thefollowing detailed description with reference to the annexed drawingsshowing in FIGURE 1 the new cutter in an elevation, partly in section.FIG- URE 2 is an axial sectional view of the new cutter. FIGURE 3 is alike view of the cutter in position on a hollow shaft and during thecutting operation, FIGURES 4, 5, and 6 are horizontal sections alonglines IV-IV, VV, VI-VI of FIGURES l, 2, 3 respectively. FIG. 7 shows afront elevation of a milling cutter.

FIG. 8 shows a side elevation of the same, partly in section, as seen inthe direction of arrow VIII of FIG. 7.

FIG. 9 is a section of the milling cutter along line IX--IX of FIG. 8.

A sleeve 1 is provided at its lower end with a set of circumferentialteeth 10. The sleeve will 'have a diameter suitable for the diameter ofthe bore hole and that of the drill pipes or drill collar. In the wallof sleeve 1 there are provided two pairs of diametrically opposedcut-outs or openings 35 in which are articulated by means of pins 2downwardly extending arms 3 which at their lower ends carry millingcutters 33 and 34. The arms and cutters are of such crosswise dimensionthat they can be accommodated within the thickness of the wall of thesleeve. In the example shown four such cutters are provided, evenlydistributed around the circumference of the sleeve, two cutters 33reaching slightly lower down than the two other cutters 34. The cutterson their arms 3 swing in said openings 35. Flat springs 4 are fixed atthe lowermost edge of openings 35 flush with the outside of sleeve 1 andurging arms 3 inwardly.

At its upper end sleeve 1 has an internal screw thread 5 so that in theconventional way the sleeve can be lowered into the bore hole at the endof a piece of pipe 8, to the upper end of which another pipe is screwedand so on to be finally fixed to a drive for rotating. Near the lowerend of sleeve 1 two pairs of detents 12 are provided adapted to lie flatat the inner face of sleeve 1 and urged by springs 13 or by their ownweight into horizontal position so as to lie athwart the interior of thesleeve. Within sleeve 1 a short piece of tube 11 is slidably supportedfor a purpose yet to be described.

When it is desired to retrieve a shaft from a bore hole and to cut 01?the shaft or a fouled drill the sleeve 1 is slipped, at the mouth of thebore hole, over the upper end of the shaft. At that instant the shortpiece 11 being in slidable frictional fit within sleeve 1 holds thecutters in their position fiush with the sleeve wall. When sleeve 1 isslipped downwardly member 11 will be pushed out by the edge of thehollow shaft but still the cutters, though under the urge of springs 4,cannot snap inwardly but will lie within the wall of sleeve 1 and abutagainst the outside of the hollow shaft 14. On its way down the sleeve 1will cut through incidentally accumulated hindrances, for which purposethe teeth 10 are provided. When the tool has arrived at the positionwhere it is to cut, the cutters 33 will be in position on the shaft 14and so will be the cutters 34 but at a slightly higher level. Thecutting operation can now be started by rotating sleeve 1 about itsaxis. All four milling cutters will start milling a groove into the wallof the hollow shaft 14. Cutters 34 mill a groove to a certain depth andthen their arms 3 will apply themselves to the edge of the milled grooveand no further deepening of the cut will be obtained by these cutters.However, the groove cut by cutters 34 will permit the Working face ofcutters 33 to penetrate deep enough to cut through the wall without arm3 striking against the edge of the groove and preventing furtherpenetration. This is so because the edge of the groove cut by cutters 33has previously been removed by cutters 34 (see FIGURE 3). When cutters33 have cut fully through the wall of the shaft and severed it above thedrill it is possible to retrieve the shaft. This is done by pulling upsleeve 1. Detents 12 urged inwardly by springs 13,, will then engageunder the cut edge and will pull up the whole shaft together with theupwardly moving tool. If necessary, the operation may be repeated i.e. adrill collar may be cut into several pieces which may be lifted oneafter another. Cutting of a drill collar will take up to four hours with40-45 r.p.m. Cooling of the cutter may be performed by mud or watercirculation as known per so.

What I claim is:

1. Apparatus for cutting drill collars and drill pipes in bore holescomprising, in combination, a sleeve having means for connection torotational drive means, said sleeve having a longitudinal axial boreslidably receiving a hollow drill shaft therewithin, said sleeve havingwall portions defining a plurality of circumferentially spaced apartcutouts, at least two pairs of milling cutters having working facesfacing inwardly of said bore, each of said milling cutters beingarticulated within said cutouts, one pair of said cutters having saidworking faces at a higher level than the level of the remaining millingcutters and being adapted to cut a groove which overlaps the groove cutby said remaining milling cutters, and spring means yieldably urgingsaid cutters radially inwardly of said longitudinal bore of said sleeve.

2. Apparatus for cutting drill collars and drill pipes in bore holes asclaimed in claim 1, wherein the lower edge of the sleeve is providedWith teeth.

3. Apparatus for cutting drill collars and drill pipes as claimed inclaim 1, further comprising detents supported adjacent to the lower edgeof the sleeve urged into horizontal position to lie athwart the interiorof the sleeve.

4. Apparatus for cutting drill collars and drill pipes as claimed inclaim 1, further comprising a short piece of tube of an outside diametersubstantially equal to the inside diameter of the sleeve and adapted tobe inserted into the sleeve to retain the cutters in retractableposition.

References Cited in the file of this patent UNITED STATES PATENTS

